157P/Tritton (0157P)

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Type: Periodic Perihelion date: 9 September 2022 Perihelion distance (q): 1.6 Aphelion distance (Q) : 5.5 Period (years): 6.7 Eccentricity (e): 0.56 Inclination (i): 12.4 JPL orbit diagram COBS lightcurve Keith Tritton (U. K. Schmidt Telescope Unit, Coonabarabran) discovered this comet on a deep IIIa-J exposure made with the 122-cm Schmidt telescope on 11 February 1978. Moonlight made observations impossible during the last half of February 1978 and during the early days of March; however, the comet was found by J. H. Bulger (Harvard Observatory's Agassiz Station) on 10 March. He gave the nuclear magnitude as 20. The last three observations of the comet were obtained by Shao on 11, 13 and 14 March. On IAU Circular No. 3194, issued on 15 March 1978, Marsden wrote, "It is possible that the comet experienced an outburst around the time of the Harvard observation on Feb. 15...." No observations were obtained thereafter. The comet was not detected during the predicted returns of 1984, 1990 or 1996 and was presumed lost. When the new comet designation system was introduced by the International Astronomical Union in August of 1994, this comet did not receive a "P/" designation for a short- period comet, but received a "D/" designation, which meant "it would be ill-advised or impossible seriously to consider a prediction for a future return...." However, on 6 October 2003, using CCD images obtained with a 0.12-m refractor, C. W. Juels (Fountain Hills, Arizona, USA) and P. Holvorcem (Campinas, Brazil) detected a comet that proved to be on a similar orbit to the lost comet. B. G. Marsden was able to calculate a new orbit, published in IAU Circular No. 8215, issued 7 October 2003, which confirmed that it was indeed identical to comet Tritton. The comet was also recovered at its 2010 apparition. The comet experienced six close approaches to Earth and two close approaches to Jupiter during the 20th century and will make two close approaches to Earth and one to Jupiter during the next 30 years (from the orbital work of Kazuo Kinoshita): • 0.26 AU from Jupiter on 11 February 2020 (increased perihelion distance from 1.36 AU to 1.57 AU and orbital period from 6.29 to 6.67 years) • 0.91 AU from Earth on 13 November 2035 • 0.79 AU from Earth on 9 January 2043 Observations (VEMag = visual equivalent magnitude) Date 10x10 mag Error VEmag Coma ' 06-Sep-15 20.44 0.27 20.1 0.2 16-Sep-15 19.93 0.12 19.3 0.2 12-Dec-15 20.01 0.16 19.7 0.2 12-Oct-22 18.3 0.4 03-Nov-22 19.2 0.4